New modem?

The only time I've had to deal with a W35, it was an absolute clusterfuck :(

In the end, we had to get Telstra to make a change on their end, swap the APN to a different one that gave it an externally routable IP address and got around it like that. Having said that, it took the best part of 5 weeks to get them to do it. Best of luck! :(

Telstra.extranet requires an account code to be added, customer service are difficult to get this because they are either dumb and dont know how, or know what you need and want you to justify a billion reasons why you need a real IP due to the IPV4 shortage.

how do you get to the net through the modem then? Surely it must have an ip?

they give you a non-public IP, like 10.x.x.x address

basically like sitting behind your router at home, but you dont have access to the router.